Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 22 for “"Gradient Flows"”.
-
Some features of surface pressure fluctuations in turbulent boundary layers with zero and favorable pressure gradients
… of zero and favorable streamwise pressure gradient flows on the surface pressure fluctuation spectra, coherence and convective wave speeds in turbulent boundary layers for momentum Reynolds numbers from 3000 to 18,800. The acceleration parameter, pressure gradient flow. K is near 2x10⁻⁷ for …
-
Modelling of Wall Pressure Fluctuations Induced by Turbulent Boundary Layer Flow
… can be predicted to include adverse pressure gradient flows, however, favourable pressure gradient flows have not received much attention. An experiment was performed to capture the effects of the favourable pressure gradient on the power spectral density. A model was created to improve upon …
-
Transition in boundary layer flows
… investigation of transition in boundary layer flows under the influence of various freestream conditions is described.<br/><br/>Velocity profiles are obtained automatically by means of a stepper-motor driven traverse mechanism which carries a hot wire probe connected to a constant temperature …
-
Some unsteady features of turbulent boundary layers
… steady free-stream, zero and favorable pressure gradient turbulent boundary layers, the unsteadiness in the form of turbulent fluctuations was investigated. Phase ensemble-averaged flow characteristics of a large amplitude periodic unsteady turbulent boundary layer was also investigated at a …
-
Prediction of transitional boundary layer properties for CFD software in engineering flows
… Milne (1994), was tested against a variety of flows including zero and constant adverse and favourable pressure gradients, and also the varying pressure gradient Rolls Royce T3C flows. The method gives good prediction of skin friction and transition length when the start of transition was in …
-
An optimization perspective on log-concave sampling and beyond
… tools in this work—diffusions and Wasserstein gradient flows—through applications to functional inequalities, the entropic barrier, Wasserstein barycenters, variational inference, and diffusion models.
-
Geometric methods in econometrics and statistics
… estimators and the directions of most rapid (gradient) change with respect to different metrics of distance on the model. I use gradient flows to describe global evolutions on the statistical model governed by changes in a scalar functional. These flows can be used to describe economic policy …
-
Essays on Metric Spaces and Macro-Finance [védés előtt]
… sequence of these functions and the associated gradient flows. Chapter 2. relies on the mathematical concepts and characteristics from Chapter 1. and incorporates these mentioned features into the Mosco convergence of CAT(1)-space. Particularly, the Mosco convergence of a sequence of semi-convex …
-
Moduli spaces and cw structures arising from morse theory
… a Morse function on it. We consider the negative gradient flow of f. Suppose the flow satisfies transversality. This naturally defines the moduli spaces of flow lines and gives a stratication of M by its unstable manifolds. The gluing of broken flow lines can also be constructed.</p> <p>We prove …
-
Pressure signature in adverse-pressure-gradient wall bounded turbulent flows
… patterns in wall-bounded adverse pressure gradient turbulent flows. For this purpose, the experimental work has been carried out towards further understanding of this class of flows, especially when the pressure gradient is increasingly adverse. Adverse pressure gradient turbulent flows and …
-
Near-wall similarity in two- and three-dimensional turbulent boundary layers
… range of two-dimensional, (near-zero) pressure gradient flows. Static pressure, mean velocity, and direct wall shear measurements using the omnidirectional meter were completed in a pressure driven, and two different shear driven three-dimensional flows. These data were combined to evaluate ten …
-
Boundary layer development from transition provoking devices
… layer in two-dimensional, arbitrary pressure gradient flows.
-
Riemannian geometry of matrix manifolds for Lagrangian uncertainty quantification of stochastic fluid flows
… of material transport in stochastic fluid flows. In a first part, two dominant classes of techniques for extracting Lagrangian Coherent Structures are reviewed and compared and some improvements are suggested for their pragmatic applications on realistic high-dimensional deterministic ocean …
-
Turbulent Boundary Layer Superstructures Near the Wall and Their Relationship to Wall-Pressure Fluctuations
… their streamwise length under favorable pressure gradients, while their spanwise meandering gets pronounced in adverse pressure gradient flows. Results from Particle Image Velocimetry (PIV) have shown that they evolve over time and space, by merging, diverging and branching during their life, …
-
Experimental And Analytical Investigations Of Solitary Waves On A Beach
… plate sensors are restricted to zero pressure gradient flows because secondary forces on the edge of the shear plate caused by pressure gradients can introduce large errors. To address this issue, a theory is developed to analyze the pressure distribution at the edges of the shear plate and a …
-
Structure-preserving machine learning for inverse problems
… be thought of as composing discretisations of gradient flows along learnable convex potentials. Appealing to a classical result on the numerical integration of ODEs, we show that constraining the operator norms of the weight operators is sufficient to give nonexpansiveness, and additional …
-
Geometric numerical integration for optimisation
… of the dynamics of existing schemes. Discrete gradient methods from geometric numerical integration preserve structures of first-order gradient systems, including the dissipative structure of schemes such as gradient flows, and thus yield iterative methods that are unconditionally dissipative, …
Page 1 of 2